The present invention relates to a camera casing and a recycling method therefor.
Lens-fitted photo film units is a kind of handy economical camera that is preloaded with photo film before it is brought into the market. Because of their handiness and cheapness, the lens-fitted photo film units are widely used by many people. There are a variety of lens-fitted photo film units for respective photographic purposes and applications. Many types of waterproof lens-fitted photo film units have also been developed, and make it possible to photograph in water. The waterproof lens-fitted photo film unit encases a film unit body in a plastic waterproof casing that is structured to be watertight, and permits a film winding operation, a shutter release operation and other operation on the film unit body from outside the waterproof casing.
Since the waterproof casing weights on waterproof properties among all, there are many restrictions on design, so the appearance tends to be monotone. Efforts for avoiding monotony have conventionally been done by putting a bright colored sheet as an accent around the film unit body, or by providing a paper box of the film unit body with ornamental printing, before the film unit body is contained in the waterproof casing. However, unlike other ordinary types of lens-fitted photo film unit, it has been difficult to provide a waterproof lens-fitted photo film unit with a superior prominent design, or with preferable colors for users while maintaining the low cost.
To solve this problem, Japanese Laid-open Patent Application Nos. 10-3113 and 10-3114 disclose waterproof casings, wherein a colored elastomer waterproof cover is formed integrally with a transparent plastic case main body by two-color injection molding. The waterproof cover not only provides an appropriate waterproof properties, but also improves the design the waterproof casing by constituting it of transparent portions and colored portions, and thereby makes the waterproof lens-fitted photo film unit conspicuous as an article.
Japanese Laid-open Patent Application No. 11-174561 discloses a lens-fitted photo film unit that uses a casing formed from a rigid plastic and an elastomer by two-color molding. Japanese Laid-open Patent Application No. 11-109468 discloses a waterproof lens-fitted photo film unit whose waterproof casing is formed from a rigid transparent plastic, a rigid opaque plastic and an elastomer by three-color molding.
In recent years, it becomes a common sense that recycling of resources is especially important for global environmental protection. As for used lens-fitted photo film units, since they are to be submitted to photofinishers for development without the photo film being removed from the casing, a system has been developed for recycling most parts of the lens-fitted photo film unit after the photo film is removed.
However, from those casings which are formed integrally from different resin materials with largely different material structures, like the above mentioned one consisting of a rigid resin and an elastomer, original materials cannot be recovered. So it is impossible to reuse them for the same articles. Since reusable range of such casings is limited, their unit price as recycled material is very cheap. As a result, recycling cost of these kinds of casings are expensive.
The present invention is made to solve the above problems, and has an object to provide a camera casing that is good for recycling, and a recycling method that makes it possible to recycle casings efficiently at a low cost.
According to the present invention, a casing for a camera that contains the camera and allows to operate the camera from outside the casing is characterized in that the casing consists of transparent portions located in front of at least those parts of the camera which need to be exposed to external light and opaque or semi-transparent portions covering other parts of the camera, and that the transparent portions and the opaque or semi-transparent portions are formed respectively from a transparent rigid resin and an opaque or semi-transparent rigid resin by two-color injection molding. The transparent rigid resin and the opaque or semi-transparent rigid resin preferably have equal or similar physical and chemical properties to each other.
Unlike the conventional two-color forming products that consist of a rigid resin and an elastomer, the casing formed from two kinds of rigid resins by two-color injection molding makes it possible to reuse the casing as a material for reproducing the same casing while maintaining the advantage on design that the casing consists of transparent portions and bright-colored portions. That is, the casing of the present invention can be reproduced as the same product, so it makes it possible to establish a closed recycling system, and is superior in terms of recycling.
According to a recycling method for a camera casing that is formed from a transparent rigid resin and an opaque or semi-transparent rigid resin by two-color injection molding, the casing after collected is melted without distinguishing the transparent rigid resin from the opaque or semi-transparent rigid resin, to be reproduced as an opaque or semi-transparent resin, and the reproduced opaque or semi-transparent resin material is used as a material for forming the same casing newly by two-color injection molding.
It is preferable to add pigments, dyes or a transparent rigid resin to the reproduced material, for adjusting color density thereof, or add an elastic material to the reproduced material, for increasing the elasticity thereof.
The recycling method of the present invention contributes to saving labor, time and cost for recycling the casing so much that the efficiency of recycling is improved.